A video of a woman, since identified as Theresa Lund, executive director of the Harvard University Humanitarian Initiative, confronting a young mother and her biracial daughter just for playing outside their home, is going viral.

The Facebook video, posted by the mother Alyson Laliberte, shows Lund sitting on the steps of the building and accusing Laliberte and her daughter of “playing too loudly” and “disturbing her children” who were trying to take a nap upstairs.

The video starts with Lund, wearing a purple T-shirt denying that she swore at the young mother.

She then addressed Laliberte’s 3-year-old daughter directly: “You’re a sweetheart. I’m sorry we’re arguing with your mommy, she’s not being very nice.”

She then sat and just stared at Lailberte.

After a while, the young mother asked, “Are you just mad because I won’t get off my own property? I think that’s why you’re mad right now.…OK, so go back upstairs to your kids. Why are you sitting here with me?”

Lund responds, “I’m sitting here because you’re preventing my children from sleeping. Would you like me to do that to you?”

“Who is even watching your kids right now?” asked Laliberte.

Instead of replying, Lund said, “Are you one of the affordable units? Or are you one of the Harvard units?”

Social media has now branded Lund as “Sidewalk Susie” and “Naptime Nancy.”

Why didn’t she move along instead of harass this mom and what’s with the affordable housing snark? Is it because the child was brown skinned? Sounds pretty racist if you ask me #SidewalkSusie But go on and defend her fine character pic.twitter.com/yLaasbPQnP

That new SidewalkSusie vid. I can't watch it. The still photo is enuf for me. I've met her a thousand times. I recognize that sneer, the way her white body takes space while demanding answers to questions she has no authority to ask, demanding racist wants in broad daylight.

I try to give folks the benefit of the doubt, but that only forgives so much. Between stare down, entitled demands for info, elitist sneering, two-faced calm addressing a child while simultaneously insinuating her mother's in the wrong? #TheresaLund go be #RoseArmitage elsewhere.

After the backlash, Lund wrote an apology in an email to Boston Globe.

“I want to be accountable for my actions in a situation where I fell far short of my values and what I expect of myself,” she said. “This clearly wasn’t my best moment, and I have work to do to more consistently be my best self.”

She also issued an apology on Facebook saying she “should not have addressed [Laliberte’s] daughter, and there was no reason for me to ask what type of unit she lives in. I offered my sincere apology to her, her mother and her daughter in person [Sunday] morning. I love our community and am committed to engaging in dialogue and actions about how to make it more welcoming and pleasant for all of us to live in together.”

@mvanrooyen_md Do you stand by this?? The "exchange" lasted a few minutes and your protege harrassed Mrs. Laliberte's daughter!!! She is three years old...And you have the nerves to say the video was taken out of context...shame on you??? #naptimenancy Be a leader, show character pic.twitter.com/LOYilRoH4Q